Screening of Yeast Strains for Pectinolytic Activity: Effects of Different Carbon and Nitrogen Sources in Submerged Fermentations
Mustafa Oskay and Hüsniye Tansel Yalçin
DOI : 10.3844/ojbsci.2015.89.96
OnLine Journal of Biological Sciences
Volume 15, Issue 3
Twenty yeast strains were screened for pectinolytic activity, among the strains, only nine were positive for pectinase production. The best strain was Kluyveromyces marxianus NRRL-Y-1109 which gave high quantities of pectinase activity, by submerged fermentation. Different parameters such as incubation time, pH (3.5-7), temperature (20-45Â°C), nitrogen and carbon source, were optimized. The optimal incubation time, temperature and pH for pectinase production were found to be 48 h, 30Â°C and 6, respectively. Studies were conducted on the production of pectinase in submerged fermentation using agro-industrial residues such as wheat bran, grape waste, brewerâs malt, beet molasses and corncob at a concentration of 1.5% (wt./vol.). Under optimized fermentation conditions, maximal enzyme were produced when citrus pectin (4.8 U/mL) was used as the carbon source, but high enzyme production was also obtained on wheat bran (2.2 U/mL) and grape waste (1.8 U/mL) in shaking conditions (120 rpm) for 48 h. Peptone and yeast extract used together as nitrogen source gave best enzyme production. The effects of temperature (30-70Â°C), pH (3.5-8) and salt concentration (1, 2, 5 and 10%) on the pectinase activity were determined. The optimum activity was obtained when temperature 45Â°C and pH at 5.5. The enzyme was stable at 45Â°C for more than 50 min, suggesting that it is relatively thermostable and being of interests for food processing.
© 2015 Mustafa Oskay and Hüsniye Tansel Yalçin. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.